NASA spacecraft Stardust has had a successful flight to comet Wild 2. Stardust flew to within 143 miles of the nucleus of the comet and scooped up at least one milligram of dust particles from the comet’s coma in a super-low-density aerogel. It probably absorbed some of the frozen low-temperature gases and organic compounds from the coma too. The samples will be returned in a capsule when Stardust flies past Earth on January 15, 2006.

The particles will be studied to learn more about comets and the outer reaches of the solar system. Even this tiny amount of about 1,200 specks of dust can provide information on the physical and chemical conditions in the outermost parts of the solar system during its formation.

Stardust collected at least one hundred tiny particles of interstellar dust streaming through the solar system using the other side of its sample collector before it reached the comet. They will be returned to Earth too.

Stardust returned 72 pictures of the comet’s nucleus, the sharpest ever taken. Comet Wild 2 has a 3-mile wide nucleus that has a very round shape. The nucleus is covered with huge depressions up to 1,000 feet wide and 400 feet deep. They are made in the early phases of a comet’s destruction by solar heating. The surface ice is vaporized and the crust edges collapse into the vent holes made by escaping gasses. The process repeats over and over with each pass by the sun. Eventually the process strips away most of the comet’s surface, leaving a few isolated hills. The comet’s structure is weakened by the outgassing, becomes unstable, and breaks apart.